fix: Add missing dependencies to useEffect and React.memo calls (#5289)

[etrepum]

Description
The merge of #5261 caused a regression where the first value of onChange is cached indefinitely because it is not used as a dependency of the effect that is supposed to maintain it. This fixes that bug, and similar bugs in the React.memo comparisons for MemoizedElement and MemoizedText where a cached renderPlaceholder is passed down to the leaf.

Issue
Fixes: #5289

Example
See the recording in #5289 for an example of the bug. A similar one could be crafted with renderPlaceholder being cached if necessary, but it should be pretty clear from the code.

Context
There aren't really other ways to fix these issues in a localized manner. I did look into adding the eslint plugin that can help check hook dependencies but there are violations in the code that would require distracting workarounds or API changes so I opted to keep it concise.

Checks

• The new code matches the existing patterns and styles.
• The tests pass with yarn test.
• The linter passes with yarn lint. (Fix errors with yarn fix.)
• The relevant examples still work. (Run examples with yarn start.)
• You've added a changeset if changing functionality. (Add one with yarn changeset add.)

[changeset-bot]

🦋 Changeset detected

Latest commit: 386b437

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
slate-react	Patch

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[kaya-altin]

Hello, after then this version, there is a problem of not being able to focus on the first click. I think it's related to the placeholder, the issue doesn't occur when the placeholder is removed. @etrepum

Screen.Recording.2023-03-03.at.10.11.41.mov

[etrepum]

@kaya-altin the only thing this PR can do is cause components to render more often. I think you are seeing a bug related to one of the other changes that were merged since the last version you tested.